SU1333246A3 - Method of producing colour-separated images for printing - Google Patents

Abstract

The invention relates to the processes of color separation and correction used in the printing industry, and allows for the elimination of moire. For this point, the originals with the same brightness are combined into areas that fill with the number of printed dots corresponding to their brightness and transfer the obtained areas onto the recording plate. To generate random signals, the random variables of the resistor R are amplified and converted to digital form. For this, a differential amplifier 23 is provided, the output voltages of a coder are supplied to the analog-to-digital converter 24, which is fed to its input analog voltage signal. converts to an eight-digit digital signal. The digital signal remains at the output of the analog-to-digital converter 24 until the next clock signal starts the calculation of the next digital signal. 1 h; n. f-ly, 5 ill. - to CO with soyo sm

Description

The invention relates to color separation and correction processes used in the printing industry in the manufacture of multi-color printing forms.

The purpose of the invention is the elimination of moire.

The essence of the method is that the points of the original of the same brightness are combined into areas that fill with the number of printed points corresponding to their brightness, and the areas thus obtained are transferred onto the recording plate.

Moreover, the site of the same brightness choose the contour of the original.

Fig. 1 is a schematic diagram of the reading of the original; Fig. 2 is a schematic diagram for obtaining a printed matrix of printable dots; FIG. 3 is a diagram of a reader for an original; Fig. 4 is a diagram for obtaining a loop signal for areas of equal luminance; figure 5 is a diagram of a generator of random variables,

The original, when read, is divided into separate floors, which are subjected to

fine reading, and the value of co-30 TDMts TDM "1- using the mounting unit 11 corresponds to the size of the raster fields during subsequent reproduction.

The read values D, –B, 5 (FIG. 1) are stored in memory 1, connected to the analyzer 2 reference sites, to which additional memory devices 3–6 are connected, where they are remembered for platforms of the same brightness level.

printed matrix are combined into a full printed matrix and entered into memory device 12, and the matrix corresponds in magnitude to the entire field of the original, which is read (Fig.1 The matrix elements of this printed matrix contain information that, when played, indicates whether or not printed the corresponding element is a dot. The content of this matrix controls the exposure unit 13.

Ginala D., - D ,. Memory 1 and, thus, the original, are divided into a matrix of individual surface elements.

D.- 0.6-

The separation is carried out according to the desired resolution of the image details. Using the analyzer 2 reference sites, individual elements of the surface D are examined

for the values, their tonal gradations, and surface elements of approximately the same luminance are combined into sub-areas Dg, D (, DC and Dj, and stored in memory devices 3-6. The indicated platforms, if they are put together, again give the whole matrix support site.

- The memory devices 7-10 (FIG. 2) are connected to the printing matrix mounting unit 11, to which the memory device 12 is connected for storing

the entire printed matrix. Next, an exposure unit 13 is connected to memory device 12 with which color-separated images are made for printing. Devices 7-10 of the memory are private print

TDM matrix TDM

These private printed matrices TDMc, - TDMj by size

do not correspond to the sub-sites

DaD,

(Fig. 1) and contain statistically distributed small, but still printable points, which are obtained using the random value generator circuit (Fig. 3). These points together correspond to the brightness of the corresponding private surface.

Private printing matrices for this purpose are divided in rows and columns into small printing elements, the division being so small that each printing element corresponds to the value of the smaller printed point. Dividing points into these elements i. the information whether or not a point should be printed in such an element is obtained by means of a random value generator.

Then private printed matrices

DMts TDM "1- using the block 11 of installation

printed matrix are combined into a full printed matrix and entered into memory device 12, and the matrix corresponds in magnitude to the entire field of the original, which is read (Fig. 1) The matrix elements of this printed matrix contain information that, when played, indicates whether it is printed or not. in the corresponding element point. The contents of this matrix controls the exposure unit 13.

The readout unit 14 for the original (Fig. 3) consists of an Inza 16 light source 15, a mirror 17 and a first opto-electronic converter 18, a lens 19 of a second optoelectronic converter 20 and a differential amplifier 21. The original is illuminated by a source 15 of light through a lens 16. The light A reflected from the original by means of a mirror 17, which partially has a mirror surface 22 and an aperture, is divided into two parts, so that the light B reflected from the reading point is fed to the optoelectronic converter 18, and light C from the reading neighborhood focus point

A lens 19 is supplied to the opto-electronic converter 20. An electrical readout signal D is obtained, which is proportional to the light reflected from the read point and an electrical signal E that is proportional to the light reflected from the readout point. Readout signal D can be used to determine surfaces of the same brightness by analyzer 2 reference sites or to determine the contour signal for areas of the same brightness. By comparing the electrical signals D and E, one finds out whether the light beam reflected from the read point differs from the beam reflected by the neighborhoods of this point, i.e. Does it have a contour signal here? The output signal F of the differential amplifier 21 is thus the desired loop signal.

The circuit shown in Fig. 4 has input resistors R, -Rg and Rp, to which voltages U, -U, are applied. The resistor outputs are connected to the inverting input of the differential amplifier 22, and the resistor R.p is connected to the non-inverting input of the differential amplifier 22 and through another

torus RP to ground. Inverting input of the differential amplifier 22 through a resistor R | connected to the output of the differential amplifier 22, on which the voltage U ,, appears. This circuit serves to receive the loop signal when the original is not read.

as shown in FIG. 3, with a single light beam, and with a raster, for example, using a row of photodiodes, moreover, with. separate photodiodes readout signals U, - nd are supplied to the differential amplifier 22. The voltage signal given to the readout point, for example U, g, is compared with other voltage signals U, - Ug which belong to the adjacent readable points, and at the output of the differential amplifier 22 is the desired loop signal.

A circuit for receiving random signals (Fig. 3) consists of a resistor R ,, which is connected between the non-inverting input of differential amplifier 23 and ground, and the output of differential amplifier 23 is connected to an eight-bit analog-to-digital converter 24 that has a synchronization input. The inverting input of the differential amplifier 23 is connected to the middle taps of two de0

0

50

littels R

R voltage

Rii-i

g

R

1E

and C

(4 S s g and the corresponding average taps of voltage dividers are formed between the resistors R ,, and 1,

1E

as well as R.

five

or R, 4 Resistor R is a serial connection and C is connected to ground, and a resistor R j and also a serial connection R, 4 and C are connected to the output 5 of the differential amplifier 23 or, respectively, to the input of the analog-digital converter 24.

This circuit serves to generate random signals, where the random variables of the noise source voltage, i.e. resistors R ,, are amplified and digitized. For this purpose, a differential amplifier 23 is provided, the output voltages of which are supplied to the analog-to-digital converter 24, which, when applied to its input, analog voltage signal converts an eight-digit digital signal. The conversion of the instantaneous analog voltage signal is performed when the corresponding clock signal K arrives at the synchronization input. The digital signal remains at the output of the analog-digital converter until the next clock signal starts the calculation of the next digital signal.

Claims (2)

1. A method of making a color-separated image for printing by applying printed points distributed according to the law of random numbers onto a plate, the brightness being determined by the appropriate number of printing points, characterized in that, in order to eliminate the moire, the original point with the same brightness pooled into areas that fill the number of printed dots that correspond to their luminance, and transfer the resulting pads onto a recording plate. 2. Method POP.1, characterized by the fact that the sites of the same brightness are chosen along the contour of the original. 1333246v The priority for paragraph-31.07.79 according to claim 1 there: .12.09.81 under item 2. Jil ya It 7 DeZgo 1o L / 2 OttrlePtf F "/ 7 .2 FIG. Editor V. Petrash Compiled by V. Andreev Tehred L. Serdyukova Proofreader M. Demchik Order 3853/58 Circulation 420 Subscription VNIIPI State, USSR Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4